Anchor bolts are well known elements used in the foundation of a house and other buildings. These bolts perform a very important function in that they attach the wood frame of the house to the foundation wall. If the anchor bolts themselves are not properly positioned and securely attached to the foundation, they fail to perform their function, and the house may come off the foundation, especially in an earthquake.
According to preferred building standards and perhaps by local code, these bolts should be located at a maximum number of inches on center and in the center of the wall plate or mud sill. However, since anchor bolts are conventionally immersed in the wet concrete of the foundation wall after it is poured but before it hardens, they are often not correctly positioned and may be damaged by the concrete. Thus, they may be incorrectly spaced, off center, out of vertical, and/or their threads covered with concrete. Moreover, an anchor bolt is usually J-shaped or S-shaped at its lower end so that it can be hooked around the reinforcing rebar in the concrete, but insuring such a connection is difficult after the concrete is poured.
Apart from properly positioning the anchor bolts, other important features of an anchor bolt holder include durability, cost and reusability. Devices have been proposed for holding anchor bolts in proper position, but the known devices do not have all the desirable features. For example, the anchor bolt holder in Design Pat. No. Des 312,382 incorporates a sleeve or tower for receiving the head of an anchor bolt and protecting its threads, but this sleeve is subject to breakage where it connects to the base plate so its durability and reusability are compromised. The anchor bolt holder in the Adams U.S. Pat. No. 5,240,224 does not protect the threads of the anchor bolts, is unnecessarily complex, and is thus relatively more expensive. Moreover, although Adams holder can be opened to fit around an anchor bolt, the latter is not clamped in the device but must be held there by a separate clip.